1. Technical Field
The disclosure relates to a control apparatus for an internal combustion engine and a control method for an internal combustion engine, which are applied to a multi-cylinder internal combustion engine in which a first injection valve and a second injection valve are provided for each cylinder.
2. Description of Related Art
Japanese Patent Application Publication No. 2014-190243 (JP 20141 90243 A) describes a multi-cylinder internal combustion engine in which a first injection valve and a second injection valve are provided for each cylinder. Each first injection valve injects fuel into an intake passage. Each second injection valve injects fuel into a corresponding one of combustion chambers. A control apparatus for such a multi-cylinder internal combustion engine is configured to detect the degree of inter-cylinder imbalance in the amount of fuel supplied to each cylinder.
For example, as a method of detecting the above-described degree of inter-cylinder imbalance, there is known a method in which one of cylinders is set as a target cylinder and a required amount of fuel supplied into the target cylinder is reduced by a predetermined percentage. In this method, by monitoring a mode in which the rotation speed of an engine output shaft changes as a result of reducing the amount of fuel supplied into the target cylinder, the degree of inter-cylinder imbalance in the amount of fuel supplied into each cylinder is detected.